Not Even Wrong

Later this week there will be a mini-workshop at City College organized by some of the CUNY particle theorists, on the topic of Yang-Mills Theories: nonperturbative aspects. The schedule of talks is here, I’m planning on attending some of them.

Also this week, Witten is speaking at the IAS on Wednesday with the title “Operator Expansion Product of ‘t Hooft Operators”. I’d like to go down to Princeton to hear this, but have to teach here around the same time, so won’t be able to attend the talk. Maybe someone who does attend will tell us about what Witten had to say.

There’s an interesting new particle theory blog, called Resonaances, and written by someone in the CERN Theory Group (who for now is operating anonymously as “Jester”, also commenting here). It includes reports of talks at the recent Winter School on Strings, Supergravity and Gauge Theories, discussion or recent ideas about supersymmetry breaking using metastable vacua, and scary photos from the Christmas party, which included someone playing a Borat/Theorat character and Wolfgang Lerche as the string pope, intoning the following prayer:

Our Witten, which art in Princeton,
Hallowed be thy name.
Thy Nobel come,
Thy will be done,
In CERN as it is in the US.
Give us this day our daily string,
And forgive us our theory,
As we forgive those who do phenomenology.
Lead us not into experiment,
And deliver us from tests.
For thine is the arXiv,
Hep-th and math-AG,
For ever and ever,
Amen

Over at Tommaso Dorigo’s blog, he’s spreading wild rumors about a Higgs signal seen by CDF. He does acknowledge that this “signal” is not the sort of thing one should take seriously, almost certainly a statistical fluctuation. With the Tevatron getting closer to the point where it might actually see the Higgs, and the LHC sooner or later starting to produce data, I look forward to the prospect of lots of rumors being put out by bloggers of Higgs or SUSY signals. I remember many years ago that there were always new rumors of things being seen at experiments, which just about always turned out to not actually be there. In recent years the large experimental collaborations have done a better job of acting responsibly and not letting wild rumors get out. Maybe the blogging phenomenon can play a useful role in getting the irresponsible rumor game going again. Any CDF/D0 people who want to send me rumors that I can then irresponsibly help propagate are encouraged to do so.

I just got a copy of a new textbook about Lie groups and their representations, called Compact Lie Groups, by Mark Sepanski. I had been frustrated that there wasn’t a book out there of just the right level with the same perspective I’m taking during the next few weeks of my graduate course, but Sepanski looks just right. From what I’ve seen so far of it, I recommend it highly as a place to learn about things like the Peter-Weyl and Borel-Weil theorems.

Another interesting book I recently acquired is Terry Gannon’s Moonshine Beyond the Monster, which is highly readable as well as entertaining, and contains a wealth of information about affine lie algebras, “modular moonshine”, vertex operator algebras and conformal field theory, and much more.

There are two new textbooks now out about string theory and attempts to get the a unified theory of particle physics out of it, by Michael Dine, and by Katrin and Melanie Becker and John Schwarz. I haven’t had a chance to look at either very carefully, but they both seem to neglect to mention that this idea doesn’t work. The thing that most amazes me though is Dine’s choice for one of the three luminaries of the field to get a blurb from that might convince people to buy the book: Lubos Motl.

Update: John Conway, the CDF experimenter whose potential Higgs signal was mentioned here, has joined the Cosmic Variance team, and his first post is one of a series giving the details of this story.

Every year the people running SPIRES put together a list of the most heavily cited papers in their database. I’ve discussed here in the past the listings for 2003, 2004 and 2005. Up until 2003 these appeared with a discussion by Michael Peskin of many of the papers on the list and their significance, but he hasn’t done this for the past couple years. This year, instead of waiting for the SLAC people to put together the list, I decided to generate one myself. I’m not enough of an expert with SPIRES to get it to just give me the list for 2006, but it was an interesting exercise to go through the lists generated by various searches just using their “topcite 50+, topcite 100+, etc…” feature, together with restrictions on dates. I think I was able to compile a complete list of papers with 150 or more citations, and post-1990 papers with 100-150. I was just looking at papers in particle theory (hep-th, hep-ph, hep-lat), not experimental (hep-ex) papers or astrophysics (astro-ph) papers, and was not counting survey articles. I’ve put the full list on a separate web-page, Most Heavily Cited Theoretical Particle Physics Papers 2006.

There are of course lots of caveats about any conclusions drawn from counting citations, but these numbers do give some solid data about what is going on these days in particle theory research. Two topics from nearly a decade ago continue to dominate these citation counts: AdS/CFT and brane-world models. By far the most heavily cited paper is the original 1997 one by Maldacena (546 citations), and the number of such citations has actually increased significantly over the number in 2004 (451) and 2005 (436). Research into AdS/CFT heavily dominates current particle theory research, but, remarkably, this research has not led to any recent heavily-cited papers on the subject. After a flurry of activity in 1998-2000, the only 21st century paper on the topic with over 100 citations in 2006 is the 2002 paper on pp-wave backgrounds by Berenstein et. al.

Overall, the list provides a very depressing view of the first six years of 21st century theoretical particle physics, with only eight post-2000 papers getting over 100 citations. These break up neatly into 4 hep-th string theory papers and 4 hep-ph phenomenology papers. Besides the 2002 pp-wave paper (hep-th/0202021) the other three string theory papers are all about the landscape, with the KKLT paper (hep-th/0301240) getting by far the most citations (238), followed by hep-th/0105097 (Giddings, Kachru, Polchinski) with 150, and Susskind’s hep-th/0302219 (“The Anthropic landscape of string theory”) with 109.

The heavily cited phenomenology papers are mostly compilations of theoretical fits to experimental data: hep-ph/0201195 (parton distributions, 193 citations), hep-ph/0405172 (neutrino oscillations, 133 citations), hep-ph/0406184 (CKM matrix, 118) and hep-ph/0506083 (neutrino mass matrix, 103 citations).

While getting this list together, I also accumulated some other data, including lists of recent papers with citation counts in the range of 50-100, and will try and put this together and write about it sometime soon.

Some other data one might want to take a look at is the arXiv monthly count of submissions (I found out about this from a posting at physicsforums). It shows the number of HEP submissions growing until about 2002, more or less flat since then, although each of the last two years have shown slight declines.

I’ll avoid the temptation to make extensive editorial comment on the meaning of these numbers, but I find it hard to believe that anyone could claim that they reflect a healthy field. The domination of non-phenomenological particle theory research by landscape studies is especially disturbing.

Last summer the entire editorial board of the prestigious journal Topology resigned, in protest over the high prices that Elsevier was charging. It was announced today that a new journal called the Journal of Topology is being launched by many of the same people. It will be published by the London Mathematical Society, printed and distributed by Oxford University Press, and the first issue should appear in January 2008.

There’s a recent report from HEPAP evaluating how far along the field is towards reaching certain set “long-term goals” (where “long-term” here is not a very long time-scale).

The New York Times Science Times section has a new columnist, John Tierney. Tierney has been with the paper for a long time, writing columns about New York and on the Op-Ed page, typically from a consistently Libertarian perspective. He also has a blog (where he promises to “rethink conventional wisdom about science and society”) and explains his conversion to science journalism by writing that he “always wanted to be a scientist but went into journalism because its peer-review process was a great deal easier to sneak through.”

The Templeton-funded magazine Science and Spirit, dedicated to bringing science and religion together, has a new issue out. It contains an interview with Max Tegmark about the Foundational Questions Institute. There’s also an article called The World on a String about the anthropic landscape and the problems with string theory. Susskind and Wilczek are quoted saying positive things about the multiverse, Krauss and I on the other side of the question. Finally there’s a review of my book by David Minot Weld with the title Stringing Us Along. It’s pretty accurate, although it’s not true that the book describes string theory as “totally without scientific merit” (that would be the string theory anthropic landscape…). Weld appears to be the son of ex-Massachusetts governor William Weld.

The Templeton foundation has a new web-site, and has announced a moratorium on new proposals over the next few months while they change their grant-making process. The web-site gives various information about the grants they have made in the past. I hadn’t realized that they make grants in mathematics. There was one last summer for about $16,000 to W. Hugh Woodin for research in mathematical logic.

New institutes devoted to “foundations” appear to be popular, with Templeton Prize winner Paul Davies starting up one at Arizona State University to be called Beyond: Institute for Fundamental Concepts in Science. This was announced by ASU president Michael Crow, who before he left for ASU was Executive Vice Provost here at Columbia and in charge of overseeing research and various “strategic initiatives”.

In the bookstore this past weekend I saw a new glossy book from National Geographic called Theories For Everything: An Illustrated History of Science. Lots about physics, but as far as I could tell, no mention of the Standard Model, Glashow, Weinberg, QCD, etc, but a whole page about string theory. In their version of physics history, one skips from Feynman to black holes, Hawking and string theory.

The coverage of string theory in popular media these days is decidedly mixed. A couple weeks ago I attended a performance of the play “Strings” by Carole Bugge, for a review, see here. It wasn’t bad as a play, and reminded me of another similar one from a couple years back, String Fever. But I’m kind of dubious that this sort of thing actually communicates any accurate understanding of physics to anyone. The play deals with themes of adultery, loss and 9/11 with a plot based on the train ride supposedly during which Steinhardt and Turok came up with the ekpyrotic scenario (the play’s train ride is jazzed up with a woman cosmologist, who is sleeping with the two other physicists). Unfortunately the playwright’s understanding of all this seems to be based on little more than watching a British TV show on the topic. In the pamphlet distributed to the audience various popular books on string theory and physics are recommended, together with much more dubious sources, like the film “What the Bleep Do We Know?”

There does seem to be a much more skeptical take on string theory getting out into the media these days. A recent episode of Numb3rs featured Judd Hirsch telling his genius mathematician son Charlie that string theory is “bogus”, more or less the same insight into the universe as that of late sixties hippies, everything is “vibes”. String theorist Larry has been shot off into earth orbit for some reason.

As mentioned here and at Cosmic Variance, the New Yorker recently actually ran a cartoon about the string theory controversy. If that’s not an indication that something has made it into the zeitgeist, I don’t know what is. Besides the New Yorker, string theory features in Zippy the Pinhead and recent Doonesbury cartoons, as well as one from Rodrigo Alonso entitled Pulling Strings that he sent me recently.

Update: What is it with Harvard string theorists and climate change?

This week I’m getting ready for the start next week of the spring semester. I’ll be teaching the second half of our graduate course on Lie Groups and Representations, something I also did a few years ago, at which point I wrote up some notes and put them on-line. This year, since the students covered somewhat different material during the first semester, I’ll be covering some different topics, hoping to both write up some notes on the new topics, and improve the older notes. We’ll see how much of that I have time for. Throughout academia, others are also trying to figure out what they’ll be talking about during the new term, for example see Clifford Johnson’s recent posting. He’s teaching a course on string theory, something about which he seems to be a tad bit defensive. Actually his outline syllabus doesn’t really indicate what he will cover, referring to aspects of perturbative and non-perturbative string theory, gravity and quantum field theory, which pretty much includes most of modern physics. Perhaps, like some of the rest of us, he hasn’t quite yet decided what exactly to talk about…

A future course that some people might be interested in is a summer school to take place in Seattle on Lattice QCD and its Applications.

An American Physics Student in England has a review of QFT textbooks for beginners. He neglects to mention a couple of my favorites (maybe just because they are ones I learned from during my student days): Quantum Field Theory by Itzykson and Zuber, and Pierre Ramond’s Field Theory: A Modern Primer.

I saw the above link first at Dorigo Tommaso’s blog, which also contains all sorts of news about interesting results coming out of the Tevatron, including a new, more accurate value of the W-mass. See for instance here, here, here, and here. About the new W-mass measurement, there’s also a Fermilab press release, and an article in Nature. It may yet turn out that the Tevatron is the place where the Higgs is first seen.

Also in Nature is an interesting article by Frank Wilczek about recent lattice QCD results showing that QCD leads to a nucleon-nucleon potential with hard-core repulsion.

Notes from the talks at last week’s Gottingen Winterschule on Geometric Langlands are now available.

From Peter Teichner’s web-site, a new preprint by him, Hohnold and Stolz describing 8 different models for real K-theory, one of which is in terms of supersymmetric quantum mechanics. The paper is dedicated to the memory of Raoul Bott, whose periodicity theorem is a large part of this story.

From Michael Douglas’s web-site, there are slides from his recent colloquium talk here at Columbia on Supersymmetric Gauge Theory: an overview. He also has a new preprint out with Denef and Kachru entitled Physics of String Flux Compactifications. The autthors go over the arguments for the Landscape and devote significant space to discussing whether or not string theory is testable. They explain why hopes that one could use a statistical, anthropic argument to predict whether supersymmetry breaking happens at low or high scales haven’t worked out. There’s a somewhat mystifying claim that “in fact string/M-theory does predict a definite distribution of gauge theory and matter contents”, referring to various papers which don’t contain anything like a definite string/M-theory prediction of such a distribution.

As for the testability of string theory, the authors first note that while there are all sorts of exotic phenomena that one might imagine finding that are consistent with string theory, none of them are required by string theory, so:

Thus, while string theory can offer experimentalists many exciting possibilities, there is little in the way of guarantees, nor any clear way for such searches to falsify the theory.

They then go on to give what they see as four possibilities for testability:

1. “Swampland” arguments showing that string theory can’t possibly lead to a low energy effective theory that agrees with what we see. Unfortunately, there seems to be no such plausible argument, with all arguments of this kind so far only ruling out string theory as a source for very different physics than what we observe.

2. String theory must be true because there is no other possible theory of quantum gravity. They completely ignore LQG, but do admit that “one should not take this too seriously until it can be proven that alternatives do not exist”, mentioning the possibility of finiteness of N=8 supergravity.

3. Maybe the LHC will discover new physics that clearly is the result of a string theory compactification.

4. Maybe they will be able to make statistical predictions using the landscape.

These seem to me extremely weak and problematic arguments. 3 appears to be little more than wishful thinking that a miracle will happen and save the day, and all efforts over the last few years to pursue 4 seem to lead to insuperable difficulties for very fundamental reasons. In the end, the authors acknowledge this, writing “ultimately convincing evidence for string theory will have to come from observing some sort of exotic physics”, and putting their hopes in string cosmology, especially the hope of seeing networks of cosmic superstrings or signals in the CMB corresponding to non-linearities in the DBI action.

After this dismal summary of the situation and of prospects for the future, the authors decide to end with conclusions more or less directly opposite to the ones their arguments naturally lead to:

We conclude by noting that while the present situation is not very satisfactory, there is every reason to be optimistic… There are many well-motivated directions for improving the situation, and good reasons to believe that substantial progress will be made in the future.

Update: One more. There will be a public debate over the anthropic principle later this month, involving David Gross, Lenny Susskind, and others. More information here.

When I was young, my main scientific interest was in astronomy, and to prove it there’s a very geeky picture of me with my telescope on display in my apartment, causing much amusement to my guests (no way will I ever allow it to be digitized, I must ensure that it never appears on the web). By the time I got to college, my interests had shifted to physics, and since that time I’ve hardly at all kept up with what is going on in astronomy. Like everyone, I’m still fascinated by the amazing pictures coming out of the field, and like most particle physicists, I’m deeply jealous of astronomers for the fact that they have a wealth of exciting new data to work with, together with promising prospects of lots more to come.

This week there’s a big meeting of the American Astronomical Society going on in Seattle, producing lots of astronomy news. Many bloggers are in attendance, including Rob Knop, Steinn Sigurdsson, Phil Plait, and C.C. Petersen. Rumors that celebrity couple Sean Carroll and Jennifer Ouellette were there turned out to be partially unfounded. Lots of press releases are being generated, including one from the University of Washington full of the usual overhyped claims about cosmic superstrings.

This week’s Science has a special issue on particle astrophysics, with lots of articles worth reading, including a nice summary of the exciting things happening in the field by Adrian Cho. He reports that many experimental particle physicists have moved into the field, partly because of the opportunities there, partly because of the difficult situation of experimental particle physics, especially in the U.S. Michael Turner is quoted explaining that the particle physicists have brought to the field some ambitious ideas, due to their habit of “thinking big”:

These are not people who are afraid to ask for big things, and they’re used to people saying yes.

An example of this is the IceCube neutrino experiment being put together under the ice in Antarctica, employing 400 researchers and costing $271 million.

Turner also has an article summarizing the situation in cosmology, where he notes that many string theorists are now pinning their hopes on making some connection to the real world in this context:

Nowhere in particle physics are the stakes higher than for string theory. If string theory is to live up to its billing as “the theory of everything” rather than, as some say, a theory of nothing, it needs a home run. Because most of its current predictions exceed the reach of terrestrial laboratories, many string theorists are pinning their hopes on a cosmological home run, such as a fundamental understanding of inflation (or a more attractive alternative), a solution to the puzzle of cosmic acceleration, or insight into the nature of the Big Bang itself.

For something truly bizarre, check out the cover story of the February issue of Astronomy magazine, entitled “What if string theory is wrong?” (mentioned earlier here). It confirms me in my opinion that I shouldn’t write about things I don’t know much about, like astronomy, since it’s by an astronomer who clearly knows very little about particle physics, especially about supersymmetry:

Supersymmetry is a mathematical principle that allows force-carrying particles, such as photons and gluons, to transform into one another. It also allows the unification of gravity with other forces because its particle, which some call the graviton, can transform into one of the other force-carriers…. If extra dimensions don’t exist, then supersymmetry doesn’t either… Without supersymmetry, some physicists have proven that the energy of empty space would be so enormous the universe would instantly collapse. Only by understanding physics beyond the standard model can we hope to understand how the vacuum works and the universe’s dark side. And only string theory appears able to serve as a reliable mathematical guide to that larger universe.

Lenny Susskind provides the usual over-the-top outrageous quote:

It is hard to find a serious paper about particle phenomenology that doesn’t in some way use the tools of superstring theory.

The author seems to believe that there’s some sort of experimental evidence of string theory and that it is just like general relativity:

While string theory is sparse on experimental validation, the situation is not so different from general relativity in its early days, when difficult mathematics made calculating a prediction extremely challenging.

and somehow thinks that string theory is the only hope for the future of physics:

Without superstring theory, we’d lose the intriguing prospects for the multiverse, with its infinite and eternal creativity in spawning new universes… More immediately, dark matter and dark energy would remain imponderable enigmas, shorn of any clues about where they come from. Astronomers can live without knowing the quantum properties of gravity. But to learn that 96 percent of the cosmos is unknowable would be a bitter pill to swallow. It would be even worse for physicists. Without a logical framework in which to pose and answer questions, our inquiries into the fundamental aspects of the physical world would devolve into semantic quibbles.

Some days I think that there’s definitely a more realistic view of string theory out there, other days I’m not so sure…

Update: It seems that Edward Witten is attending the AAS meeting, although not speaking there. See the comment from David Cobden, and Steins Sigurdsson’s blog entry from the conference Trendspotting, where he reports:

On a completely unrelated note, Ed Witten was spotted wandering the halls…
Now there is always some cosmic string or quantum cosmo thingy going on here, but what we ask (and, yes, I did actually ask), was he doing in the extrasolar planet session?

Ed likes exoplanets!
Dood.

Update: Science a Gogo has an article about this, String Theory? Knot!, which uses my characterization of Susskind’s quote as “over-the-top”, but then uses the wrong quote, using something from the Astronomy magazine article which wasn’t written by Susskind.

Update: The University of Washington press release on cosmic superstrings, based upon a poster presented at the AAS meeting, has made it to Fox News (via Lubos).

As mentioned here earlier, the last Congress decided to not pass most new FY 2007 spending bills before leaving town, putting these off until the new Congress convenes, and running the government on a continuing resolution, mostly at last year’s spending levels. There is speculation that the new Congress may decide to not even try to put together and pass FY 2007 spending bills (the fiscal year started Oct. 1), instead just funding things by a continuing resolution for the rest of the year, mostly at FY 2006 levels. The Fermilab director Pier Oddone has issued a statement about the implications of having to run Fermilab at the FY 2006 funding level for the rest of the year. These would be dire, including having to take such measures as completely shutting down the lab and furloughing its employees for a month.

This would be extremely bad news for Fermilab, coming at a time when they have been having great success with getting the Tevatron to run at ever greater luminosity. The machine has just set new records for weekly luminosity, monthly luminosity, and initial luminosity (you can follow their progress here). While everyone is concentrating on the LHC, the Tevatron remains the only machine in the world running at the high-energy frontier, and the most likely source of any surprising new information about beyond standard model physics during the next couple of years. It would be a great shame if budget problems were to have a negative impact on this.

I don’t have any information about what the impact of these budget problems might be on particle theory or on mathematics. For mathematics, the impact may not be so great since, after several years of sizable budget increases at the NSF, the FY 2007 budget request for mathematics at the NSF contained only a 3.2 percent increase.

There’s a quite interesting interview in the latest (February) issue of the Notices of the AMS with William Rundell. Rundell was the director of the mathematics part of the NSF until last summer. He describes how during his tenure the NSF emphasized “single-researcher” or “PI” grants, saying that:

If you take any block of time from NSF’s beginnings to now and you ask, what were the best years for the DMS single-investigator grants or for senior researcher increases?, the answer is the period of 2001 through 2005.

Rundell notes that during this time the number of grants went up by only a small amount, maybe 10 percent, but that the value of each grant “went up enormously”. Before 2001, people were being given at most one month of “summer support”, now junior people get two months, and senior people often a month and a half or two months. While inflation and average university raises have been around 2 to 3 percent, the academic star system has had stars (the people most likely to be getting these grants) receiving 6 to 7 percent raises, 10 percent promotion raises, and big hikes in salary when they move. So, the bottom line is that a lot more money has been going to a small segment of the mathematics research community.

The interviewer states that “Most mathematicians believe PI grants are the most important part of the DMS”, but I wonder whether that is really true. Rundell also explains that the current system leaves most mathematicians with not much motivation to lobby for an increased NSF budget, especially if most of the increase is going to go to a small number of well-paid people:

I think it is probably true that the mathematicians who get the money aren’t pulling their weight for justifying us to get more. And on the other hand, those people who are disenfranchised have no incentive to do that.

Personally I’ve never understood the logic of devoting such a large part of the NSF research budget in math or theoretical physics to increasing the salary of the best paid people in the field, although I hear that once one achieves such a status the reasons become much clearer. Besides the “summer salary” though, these grants do fund many things that are important for the health of university math departments, especially supporting graduate students. Rundell claims that over this same period the NSF has doubled its support for graduate students. This is probably reflected in the data contained in another article in the new Notices, an annual survey of new doctoral recipients. This survey finds the number of Ph.D.s awarded last year in mathematics to be 1245, the highest number ever recorded. Four years ago this number was at a local minimum, with 948 mathematics Ph.Ds awarded.

Also supposedly suffering from funding problems is the high energy theoretical physics group at Harvard, where, according to one of its faculty members, because of feminism the university has been unable to afford competent computer support. As a result the group has recently had to shut down its web server (schwinger.physics.harvard.edu), and evidently has had several of its machines broken into, with no administrator around to deal with this. There’s a huge on-going problem with university computer systems which seems to be the same thing that happened at Harvard. Many groups of hackers have broken into a large number of insufficiently well-protected university unix systems, often installing trojanned versions of the SSH software. The trojanned SSH client programs then gather people’s usernames and passwords as they are typed in when SSH is used to login to another system. These are used to break in to yet other systems. Since SSH is the fundamental tool used to manage logins between different machines at most universities, this is a very difficult problem to deal with.

One reason I’ve mentioned this is to warn people to be very careful about using SSH, especially using it to login from a system not at your home university, since the SSH program on the machine you are using may be trojaned. Better to use your own laptop, with its own SSH software. I’d like to discourage posting of comments about computer security here, since most such comments just spread misinformation of one kind of another, just making problems worse. There are many other places on the internet to get information about and discuss these issues.

Update: There’s more about the 2007 NSF budget here.

Update: Today’s NY Times has an article here. It seems that many other labs, including RHIC and Jefferson Lab, are facing similar problems.

Every year John Brockman’s Edge Foundation asks a large number of people in science and technology to write a short piece answering a chosen question, and this year the question is What Are You Optimistic About?

Among particle physicists, the overwhelming thing to be optimistic about is the LHC. For instance, Lawrence Krauss writes:

I am optimistic that after almost 30 years of sensory deprivation in the field of particle physics, during which much hallucination (eg. string theory) has occurred by theorists, within 3 years, following the commissioning next year of the Large Hadron Collider in Geneva, we will finally obtain empirical data that will drive forward our understanding of the fundamental structure of nature, its forces, and of space and time.

Others who also mention the LHC include Lisa Randall, Charles Seife, Lee Smolin, Adam Bly, Maria Spiropulu, Karl Sabbagh, Frank Wilczek, Paul Steinhardt and Corey Powell.

Wilczek describes himself as optimistic that “physics will not achieve a theory of everything”, taking the point of view that he hopes nature will continue to surprise us. He also denigrates the search for a fundamental theory of everything by noting what it has led to in the case of the string theory landscape:

At this point the contrast between the grandeur of the words “Theory of Everything” and the meager information delivered becomes grotesque.

Alexander Vilenkin on the other hand is optimistic about the multiverse and the anthropic landscape, saying it is implied by string theory, “our best candidate for the fundamental theory of nature”, and that he thinks that statistical predictions will be possible.

The person I agree with most is Gino Segre who writes:

So why am I optimistic? Because I believe that controversy, with clearly drawn out opposing positions, galvanizes both sides to refine their opinions, creates excitement in the field for the participants, stimulates new ideas, attracts new thinkers to the fray and finally because it provides the public at large with an entrée into the world of science at the highest level, exhibiting for them heated arguments between great minds differing on questions vital to them. What could be more exciting?

That sort of optimistic point of view on the whole string theory controversy is one that I hope more theoretical physicists will take, with string theorists acknowledging that there are serious questions that have been raised and that are worth debating.

Personally I’m a lot more optimistic now than I was a year ago that a more realistic view of string theory has started to take hold in many quarters, and that perhaps particle theory will move towards a healthier state. Like the Edge contributors, I see the fact that the LHC is now not far off as a cause for optimism. Perhaps it will produce the sort of surprising new insight into electroweak symmetry breaking needed to show the way forward. Even if it doesn’t do this, the likely failure to see superpartners or extra dimensions may encourage theorists to give up on ideas that don’t work and try and strike out in other directions.

A random collection of links, on the whole not having anything to do with the holidays:

A Stanford Physics Student in Berkeley is now An American Physics Student in England, and reports from the DAMTP Christmas party, where people were supposed to be wearing “Sci-Fi” costumes, that one physicist came in a black t-shirt with the following printed on the front:

The Anthropic Landscape of String Theory

Leonard Susskind. hep-th/0302019

As far as I can tell, of string theory papers written during the last four years, this is the second most heavily cited (the first is the KKLT one that inspired it). How dare these English people act as if this is some sort of joke?

Raymond Streater’s Lost Causes web-site has always been a wonderful source of anecdotes and opinions. He has a new book coming out any day now from Springer entitled Lost Causes in and Beyond Physics which I’ve just ordered and am looking forward to reading. Streater’s web-site also includes a pretty hilarious commentary on Lubos Motl’s typically absurd review of one of Streater’s earlier books, the deservedly famous PCT, Spin and Statistics and All That, written with Arthur Wightman. I had never realized I was in such good company.

From Streater’s web-site I also found a link to an interesting talk by Guralnick on some of the history he was involved in of work on symmetry breaking in QFT during the sixties which ultimately led to the Glashow-Weinberg-Salam model and what is now known as the Higgs mechanism. The talk tells how leading physicists discouraged work on these ideas as “junk” that wouldn’t lead anywhere and would ensure that one couldn’t get a job. During these years the dominant opinion was that S-matrix theory was the route to future progress, with QFT a dead-end.

Back when I was a physics graduate student I remember every so often picking up a copy of the journal Foundations of Physics and flipping through it, trying to read some of the articles. From what I remember, at the time it struck me as a semi-crackpot phenomenon, mixing a few serious attempts at thinking about foundations with large heaps of nonsense. It seemed clear to me then that serious theorists worked on very different things, trying to understand gauge theories and the Standard Model. A friend of mine who was also a graduate student back in those days recently told me that now the current mainstream literature strikes him as much like that found in the old days in journals like Foundations. I don’t know what this means for physics, but Springer recently announced that Gerard ‘t Hooft (one of the main creators of gauge theory) is taking over as editor-in-chief of the journal. Maybe in times like ours in which there is no experimental guidance, work on foundations should get new emphasis (I think this is one of the points in Lee Smolin’s recent book).

If one wants an overview of recent developments in the interaction of math and physics, one could do a lot worse than read the proposal from various mathematicians and physicists in the Netherlands entitled The Fellowship of Geometry and Quantum Theory (via Klaas Landsman’s web-site).

John Baez’s student Derek Wise has a well-written paper about Cartan connections, and John provides some commentary in his latest This Week’s Finds in Mathematical Physics. I’ve always been fascinated by Cartan connections, since they provide a framework linking very general ideas about geometry with Lie groups. As John notes, they provide a joint generalization of the Riemannian and Kleinian points of view about geometry. They also seem to provide a natural mathematical framework for thinking about the relation between GR and gauge theory. Besides the references given by Wise, one should also note that Kobayshi-Nomizu, the standard reference text among mathematicians on geometry from the point of view of connections, is very much inspired by the idea of a Cartan connection. It seems likely to me that if we ever figure out how to properly understand geometrically how to unify gravity and the standard model, these ideas will be part of the story (although much else will also be required, including an understanding of the role of spinors, and of the geometry behind quantization).

Finally, for comic relief, Kris Krogh pointed me to a talk by Michael Berry from a few years ago, where he describes his experience back in 1985 at CalTech when he was working on quantum physics and zeta-functions, and met up with some of the local string theorists:

I met one of them, who asked what I was working on. When I told him, he fixed me with a pitying stare. “Yes, we have zeta functions throughout string theory. I expect the Riemann hypothesis will be proved in a few months, as a baby example of string theory.”

Update: Several people have pointed out that the Susskind t-shirt or the report about it contain a typo. The correct reference is hep-th/0302219

Update: There’s an interview with me posted on Scienceline, the web-site of the NYU Science, Health and Environmental Reporting Program, with the title Stringing Up String Theory.

Update: Yet another interview, this one with Lee Smolin at IEEE Spectrum on-line, called Thread-bare Theories.

Scott Aaronson has adopted a sensible attitude towards the controversy over string theory, announcing in a new posting entitled Mercenary in the String Wars that his allegiances in this “War” are for sale to the highest bidder. I encourage all my extremely wealthy financial backers to take him up on this.

He seems to have reached this decision after enjoying an all-expenses-paid vacation in the Bay Area courtesy of the Stanford string theorists, despite having a great deal of sympathy for the criticisms being made of string theory. While there, he gave a talk for which he makes his notes available, on the topic of Computational Complexity and the Anthropic Principle. It’s quite entertaining, although the fact that anyone is seriously debating the kind of issues Scott discusses is a good indication of how far off the rails string theory has gone.

Scott seems surprised to discover that, in private discussion, string theorists are far more reasonable than he expected from their writings, from the behavior of string theory bloggers like Lubos, and from his conversations with Greg Kuperberg, who is convinced that string theory critics are “intellectually non-serious” (I forgot to mention in my last posting that Kuperberg was someone else I had in mind when quoted in 02138). His experience agrees with my own, that in private conversation I find that most string theorists and I agree much more than one would guess. In such a context I’ve just about always found them more than willing to admit that the current situation of string theory is disturbing, progress has ground to nearly a halt, and that the whole landscape business is extremely problematic. That these attitudes are not well reflected in the public utterances of string theorists I think is due to several factors. Given the problems facing the theory, many find it best to just avoid being quoted publicly, and those who do talk to the press feel that their field is to some extent under unfair attack in the media and they should make their best effort to defend it. Those who spend their time vigorously defending string theory as a healthy research program, attacking its critics on blogs and elsewhere, often represent only a tail in the statistical distribution of views and behaviors of the string theory community.

I also suspect that one reason Scott found the Stanford string theorists behaving more reasonably than he would have guessed is that the last year or so has not been kind to their early hopes that statistical calculations would allow some sort of real predictions to emerge from the anthropic landscape. It has become increasingly clear that this kind of idea just can’t work, for reasons that have been extensively discussed here.

I predict a lively discussion in the comment section over at Scott’s blog, and encourage people to use that venue. Already John Preskill has weighed in with what he thinks is an unintentional double entendre about Susskind: “When I listen to Lenny Susskind, I really believe that information can come out of a black hole.”

Update: Scott is pretty funny, but I have to admit that Lubos is completely hilarious.